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/*
* Copyright 2017 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "pc/ice_server_parsing.h"
#include <stddef.h>
#include <cctype> // For std::isdigit.
#include <string>
#include "p2p/base/port_interface.h"
#include "rtc_base/arraysize.h"
#include "rtc_base/checks.h"
#include "rtc_base/ip_address.h"
#include "rtc_base/logging.h"
#include "rtc_base/socket_address.h"
namespace webrtc {
// Number of tokens must be preset when TURN uri has transport param.
static const size_t kTurnTransportTokensNum = 2;
// The default stun port.
static const int kDefaultStunPort = 3478;
static const int kDefaultStunTlsPort = 5349;
static const char kTransport[] = "transport";
// NOTE: Must be in the same order as the ServiceType enum.
static const char* kValidIceServiceTypes[] = {"stun", "stuns", "turn", "turns"};
// NOTE: A loop below assumes that the first value of this enum is 0 and all
// other values are incremental.
enum ServiceType {
STUN = 0, // Indicates a STUN server.
STUNS, // Indicates a STUN server used with a TLS session.
TURN, // Indicates a TURN server
TURNS, // Indicates a TURN server used with a TLS session.
INVALID, // Unknown.
};
static_assert(INVALID == arraysize(kValidIceServiceTypes),
"kValidIceServiceTypes must have as many strings as ServiceType "
"has values.");
// |in_str| should follow of RFC 7064/7065 syntax, but with an optional
// "?transport=" already stripped. I.e.,
// stunURI = scheme ":" host [ ":" port ]
// scheme = "stun" / "stuns" / "turn" / "turns"
// host = IP-literal / IPv4address / reg-name
// port = *DIGIT
static bool GetServiceTypeAndHostnameFromUri(const std::string& in_str,
ServiceType* service_type,
std::string* hostname) {
const std::string::size_type colonpos = in_str.find(':');
if (colonpos == std::string::npos) {
RTC_LOG(LS_WARNING) << "Missing ':' in ICE URI: " << in_str;
return false;
}
if ((colonpos + 1) == in_str.length()) {
RTC_LOG(LS_WARNING) << "Empty hostname in ICE URI: " << in_str;
return false;
}
*service_type = INVALID;
for (size_t i = 0; i < arraysize(kValidIceServiceTypes); ++i) {
if (in_str.compare(0, colonpos, kValidIceServiceTypes[i]) == 0) {
*service_type = static_cast<ServiceType>(i);
break;
}
}
if (*service_type == INVALID) {
return false;
}
*hostname = in_str.substr(colonpos + 1, std::string::npos);
return true;
}
static bool ParsePort(const std::string& in_str, int* port) {
// Make sure port only contains digits. FromString doesn't check this.
for (const char& c : in_str) {
if (!std::isdigit(c)) {
return false;
}
}
return rtc::FromString(in_str, port);
}
// This method parses IPv6 and IPv4 literal strings, along with hostnames in
// standard hostname:port format.
// Consider following formats as correct.
// |hostname:port|, |[IPV6 address]:port|, |IPv4 address|:port,
// |hostname|, |[IPv6 address]|, |IPv4 address|.
static bool ParseHostnameAndPortFromString(const std::string& in_str,
std::string* host,
int* port) {
RTC_DCHECK(host->empty());
if (in_str.at(0) == '[') {
std::string::size_type closebracket = in_str.rfind(']');
if (closebracket != std::string::npos) {
std::string::size_type colonpos = in_str.find(':', closebracket);
if (std::string::npos != colonpos) {
if (!ParsePort(in_str.substr(closebracket + 2, std::string::npos),
port)) {
return false;
}
}
*host = in_str.substr(1, closebracket - 1);
} else {
return false;
}
} else {
std::string::size_type colonpos = in_str.find(':');
if (std::string::npos != colonpos) {
if (!ParsePort(in_str.substr(colonpos + 1, std::string::npos), port)) {
return false;
}
*host = in_str.substr(0, colonpos);
} else {
*host = in_str;
}
}
return !host->empty();
}
// Adds a STUN or TURN server to the appropriate list,
// by parsing |url| and using the username/password in |server|.
static RTCErrorType ParseIceServerUrl(
const PeerConnectionInterface::IceServer& server,
const std::string& url,
cricket::ServerAddresses* stun_servers,
std::vector<cricket::RelayServerConfig>* turn_servers) {
// RFC 7064
// stunURI = scheme ":" host [ ":" port ]
// scheme = "stun" / "stuns"
// RFC 7065
// turnURI = scheme ":" host [ ":" port ]
// [ "?transport=" transport ]
// scheme = "turn" / "turns"
// transport = "udp" / "tcp" / transport-ext
// transport-ext = 1*unreserved
// RFC 3986
// host = IP-literal / IPv4address / reg-name
// port = *DIGIT
RTC_DCHECK(stun_servers != nullptr);
RTC_DCHECK(turn_servers != nullptr);
std::vector<std::string> tokens;
cricket::ProtocolType turn_transport_type = cricket::PROTO_UDP;
RTC_DCHECK(!url.empty());
rtc::tokenize_with_empty_tokens(url, '?', &tokens);
std::string uri_without_transport = tokens[0];
// Let's look into transport= param, if it exists.
if (tokens.size() == kTurnTransportTokensNum) { // ?transport= is present.
std::string uri_transport_param = tokens[1];
rtc::tokenize_with_empty_tokens(uri_transport_param, '=', &tokens);
if (tokens[0] != kTransport) {
RTC_LOG(LS_WARNING) << "Invalid transport parameter key.";
return RTCErrorType::SYNTAX_ERROR;
}
if (tokens.size() < 2) {
RTC_LOG(LS_WARNING) << "Transport parameter missing value.";
return RTCErrorType::SYNTAX_ERROR;
}
if (!cricket::StringToProto(tokens[1].c_str(), &turn_transport_type) ||
(turn_transport_type != cricket::PROTO_UDP &&
turn_transport_type != cricket::PROTO_TCP)) {
RTC_LOG(LS_WARNING) << "Transport parameter should always be udp or tcp.";
return RTCErrorType::SYNTAX_ERROR;
}
}
std::string hoststring;
ServiceType service_type;
if (!GetServiceTypeAndHostnameFromUri(uri_without_transport, &service_type,
&hoststring)) {
RTC_LOG(LS_WARNING) << "Invalid transport parameter in ICE URI: " << url;
return RTCErrorType::SYNTAX_ERROR;
}
// GetServiceTypeAndHostnameFromUri should never give an empty hoststring
RTC_DCHECK(!hoststring.empty());
int port = kDefaultStunPort;
if (service_type == TURNS) {
port = kDefaultStunTlsPort;
turn_transport_type = cricket::PROTO_TLS;
}
if (hoststring.find('@') != std::string::npos) {
RTC_LOG(WARNING) << "Invalid url: " << uri_without_transport;
RTC_LOG(WARNING)
<< "Note that user-info@ in turn:-urls is long-deprecated.";
return RTCErrorType::SYNTAX_ERROR;
}
std::string address;
if (!ParseHostnameAndPortFromString(hoststring, &address, &port)) {
RTC_LOG(WARNING) << "Invalid hostname format: " << uri_without_transport;
return RTCErrorType::SYNTAX_ERROR;
}
if (port <= 0 || port > 0xffff) {
RTC_LOG(WARNING) << "Invalid port: " << port;
return RTCErrorType::SYNTAX_ERROR;
}
switch (service_type) {
case STUN:
case STUNS:
stun_servers->insert(rtc::SocketAddress(address, port));
break;
case TURN:
case TURNS: {
if (server.username.empty() || server.password.empty()) {
// The WebRTC spec requires throwing an InvalidAccessError when username
// or credential are ommitted; this is the native equivalent.
RTC_LOG(LS_ERROR) << "TURN server with empty username or password";
return RTCErrorType::INVALID_PARAMETER;
}
// If the hostname field is not empty, then the server address must be
// the resolved IP for that host, the hostname is needed later for TLS
// handshake (SNI and Certificate verification).
const std::string& hostname =
server.hostname.empty() ? address : server.hostname;
rtc::SocketAddress socket_address(hostname, port);
if (!server.hostname.empty()) {
rtc::IPAddress ip;
if (!IPFromString(address, &ip)) {
// When hostname is set, the server address must be a
// resolved ip address.
RTC_LOG(LS_ERROR)
<< "IceServer has hostname field set, but URI does not "
"contain an IP address.";
return RTCErrorType::INVALID_PARAMETER;
}
socket_address.SetResolvedIP(ip);
}
cricket::RelayServerConfig config =
cricket::RelayServerConfig(socket_address, server.username,
server.password, turn_transport_type);
if (server.tls_cert_policy ==
PeerConnectionInterface::kTlsCertPolicyInsecureNoCheck) {
config.tls_cert_policy =
cricket::TlsCertPolicy::TLS_CERT_POLICY_INSECURE_NO_CHECK;
}
config.tls_alpn_protocols = server.tls_alpn_protocols;
config.tls_elliptic_curves = server.tls_elliptic_curves;
turn_servers->push_back(config);
break;
}
default:
// We shouldn't get to this point with an invalid service_type, we should
// have returned an error already.
RTC_NOTREACHED() << "Unexpected service type";
return RTCErrorType::INTERNAL_ERROR;
}
return RTCErrorType::NONE;
}
RTCErrorType ParseIceServers(
const PeerConnectionInterface::IceServers& servers,
cricket::ServerAddresses* stun_servers,
std::vector<cricket::RelayServerConfig>* turn_servers) {
for (const PeerConnectionInterface::IceServer& server : servers) {
if (!server.urls.empty()) {
for (const std::string& url : server.urls) {
if (url.empty()) {
RTC_LOG(LS_ERROR) << "Empty uri.";
return RTCErrorType::SYNTAX_ERROR;
}
RTCErrorType err =
ParseIceServerUrl(server, url, stun_servers, turn_servers);
if (err != RTCErrorType::NONE) {
return err;
}
}
} else if (!server.uri.empty()) {
// Fallback to old .uri if new .urls isn't present.
RTCErrorType err =
ParseIceServerUrl(server, server.uri, stun_servers, turn_servers);
if (err != RTCErrorType::NONE) {
return err;
}
} else {
RTC_LOG(LS_ERROR) << "Empty uri.";
return RTCErrorType::SYNTAX_ERROR;
}
}
// Candidates must have unique priorities, so that connectivity checks
// are performed in a well-defined order.
int priority = static_cast<int>(turn_servers->size() - 1);
for (cricket::RelayServerConfig& turn_server : *turn_servers) {
// First in the list gets highest priority.
turn_server.priority = priority--;
}
return RTCErrorType::NONE;
}
} // namespace webrtc